In this paper, gas dynamics and temperature distribution of a transient impinging jet, typically used to deliver powdered drug or vaccines ballistically to the skin, have been numerically simulated. Calculations were performed with the unsteady compressible Navier-Stokes equations, solved using a modified implicit flux vector splitting (MIFVS) difference scheme with a modified k-e model. After validation against an experimental underexpanded jet-flow test cast, the code was applied to two biolistic configurations. Firstly, calculated pressure histories were compared with corresponding measurements in an unsilenced biolistic device, with good agreement. Secondly, this calculation was extended to a silenced geometry, with an emphasis on the gas properties immediately above a skin target. A peak stagnation gas temperature of 420°C is revealed within 175 μs of diaphragm rupture. The temperature of the following driver helium gas suddenly drops to below - 100°C before approaching ambient temperature within 1 ms. The effect of this impinging jet on the human skin is subsequently explored by a one-dimensional convection heat transfer model. On the skin surface, a peak fluctuation of [+5.5°C, - 4.5°C] is.recorded during the operation process. Beyond the outer skin layer, called the stratum corneum (i.e. > 10.6μ), temperature deviations from the normal condition are trivial. Therefore, the heat transfer between the biolistic jet and skin is negligible. This result is consistent with pain-free clinical trial observations.
The deamination of unmodified cytosine to uracil by treatment with bisulfite has for decades been the gold standard for sequencing epigenetic DNA modifications including 5methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC). However, this harsh chemical reaction degrades the majority of the DNA and generates sequencing libraries with low complexity. Here, we present a novel bisulfite-free and base-resolution sequencing method, TET Assisted Pic-borane Sequencing (TAPS), for detection of 5mC and 5hmC. TAPS relies on mild reactions, detects modifications directly without affecting unmodified cytosines and can be adopted to detect other cytosine modifications. Compared with bisulfite sequencing, TAPS results in higher mapping rates, more even coverage and lower sequencing costs, enabling higher quality, more comprehensive and cheaper methylome analyses.
One Sentence Summary:A bisulfite-free and base-resolution method to directly sequence epigenetically modified cytosine.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.